Fitting a Rohloff to a Cross Check can be done but it would be a bit clumsy because you would have to use the Rohloff torque arm. I have a Moonlander with a Rohloff and I'm currently building a Troll with a Rohloff as a touring bike. I'd say, if you can afford it, get a frame that can take a Rohloff without that ugly torque arm. One can never have enough bikes, right?